L2 - taxonomy + phylogeny Flashcards
importance of bacteria to our lives
disease causing; most bacteria not pahtogenic. food production, additives, drug production, wastewater treatment.
great metabolic diversity
genetic source/cellular scaffold for recombinant DNA biotech
why does “species” not really work for bacteria
definition = reproduce + form fertile offspring. bacteria dont reproduce.
life on earth from hydrothermal systems
sub-marine mounds from prebiotic incubators = life originated
theory: life began in RNA world
RNa catalytic + self-replicating. catalyzed own synthesis. RNA has more complex forms than DNA, so folded + translated a protein for catalysis = became info + metabolic molecule. still remant
some characteristics so common they mustve been in LUCA
chirality of molecules, presence of ribosomal RNA, mechanisms of DNA repln
how gene transfer contributed to early life
horizontal gene transfer btw bacteria. swapped info easily, if not good = lost. differentiate + specialize over time; protect what u build with barriers/membrane.
anoxic earth + microbe metabolism
anoxic therefore anaerboic metabolism.
CO2, use N2, use light or oxidation of H2.
metabolism had impact on surrounding enviro.
-> when O2 rose formed ozone = necessary for land-life
main things we need to know about how an organism lives
source of energy, electrons, carbon + oxidant.
bacteria around O2 and H2S
-> cyanobacteria + phototrophs
catalyst for reaction btw the two compounds. carbon fixation .
evidence for rise of O2
iron oxide bands = iron in anoxic oceans, with O2, precipitates = banded iron formation.
what is the great oxidation event?
increase in O2 . about 99% of organisms died. but those that could handle stayed alive
universal tree of life based on?
rRNA. 3 domains: bacteria, Archaea, eukarya.
root= LUCA
three domain concept through analysis of central cellular function genes
60+ genes shared by nearly all cells.
- euk + archaea more similar.
LUCA was probs prokaryotic with DNA genome + ability to transcribe/translate protein.
what are 3 types of RNA?
tRNA (aa to ribosome); mRNA (encodes AA sequence of protein; rRNA ( complex with ribosomal protein)
large + small subunits of rRNA
small: 16s = bacteria, archaea, mt, chloroplast;; 18s = euk
large: 5s+23s (50s): bacteria, archaea, mt, chloro. ;; 5s + 5.8S + 28s (60S) euk
